An important goal in the development of modern internal combustion engines is a reduction of pollutant emission. A purpose of development activities is an optimization of exhaust cleaning systems. Modern exhaust cleaning systems currently achieve pollutant conversion rates of over 97%.
Increasing atmospheric pollution in nearly all countries has led to increasingly stringent limitation on pollutant emission. To assure repeatability and comparability, various testing methods, evaluations and limits have been considered. For example, in regard to limits in the USA, there is the category ULEV (Ultra Low Emission Vehicle) and the category with the strictest limits at this time of SULEV (Super Ultra Low Emission Vehicle).
For cleaning the air needed for combustion in the internal combustion engines, air filter systems are known, especially filter elements for the air entering at the front-end. These filters are for example wound with filter layers which are alternately flat and corrugated in shape. Thus passages are formed which by an alternating blockage force the flow through the filter medium. Thus the medium being filtered passes through passages open at the front end on the entry end of the filter and alternates within the filter element in passages which are open at the exit end and are adjacent to the entry passages. Thus a filtration of the fluid takes place.
For example, DE 10063789A discloses a filter element for entry at the front end, which has triangular passages that are closed alternately such that, by flowing from an entry end to an exit end, the fluid to be filtered must pass through the filter material. The passages are formed by the alternate application of flat layers and folded layers, in which all ends of the inflow passages lead into passages at the outflow end.
In PCT/WO 200050149 a filter element is disclosed having first and second flow ends opposite one another. The filter medium consists of a folded construction in which the folds are divided into an upper and a lower series of passages. The upper row of passages is closed at the outflow end, while the lower row of passages is closed at the entry end.
As a consequence of the above-described SULEV/ULEV problem, it is disadvantageous, however, that due to the lack of materials that are capable of binding hydrocarbons, the hydrocarbons present in the intake tube of an internal combustion engine can enter into the environment.
It is therefore a problem for the present invention to avoid the described disadvantages of the state of the art and create an active carbon coated filter element which can be arranged in the air intake tract of an internal combustion engine and reliably reduce the emissions of a vehicle.